Treesearch

Statistics are presented by county for western Oregon for four dominant land use classes on non-Federally owned land. The classes were primary forest, primary agriculture, low-density urban, and urban. Classes were determined from aerial photographs taken in 1971-74 and in 1982; by using these data, estimates of change for the period between photography were developed.

The impact of log defects on lumber recovery and the accuracy of cubic log scale deductions were evaluated from log scale and product recovery data for more than 3,000 logs. Lumber tally loss was estimated by comparing the lumber yield of sound logs to that of logs containing defects. The data were collected at several product recovery studies; they represent most of the major commercial softwood species in the Western United States. Defects listed in order of decreasing effect on lumber recovery are: multiple defects, ring shake, soft rot and voids, weather check, firm rot, breakage,...

A new procedure is presented for estimating carrying capacity (the number of animals of a given species that can be supported per unit area of habitat) on the basis of two simultaneous nutritional constraints. It requires specifying the quantity (bio-mass) and quality (chemical composition or digestibility) of available food and the nutritional requirements of the animal species. Its application is illustrated with an example involving black-tailed deer (Odocoileus hemionus sitkensis) in four forest habitats during summer and winter with three sets of snow conditions and two levels of...

The Budworm Model predicts the amounts of foliage destroyed annually by the western spruce budworm, Choristoneura occidentalis Freeman, in a forest stand. The model may be used independently, or it may be linked to the Stand Prognosis Model to simulate the dynamics of forest stands. Many processes that affect budworm population dynamics are simulated in detail, including budworm and host phenology, larval growth and feeding, larval and adult dispersal, and the effects of natural enemies. This publication describes the structure, assumptions, and default parameter values of the Budworm Model.

The 1978 inventory of the forest resources of Prince William Sound and Afognak Island was designed to produce estimates of timberland area, volumes of timber, and growth and mortality of timber. Estimates of timber resource quantities were also categorized by owner. Nearly 56 percent of the available timberland area is under Forest Service management, and almost 40 percent is held by private interests. Total available timberland area was estimated at 648,454 acres. Cubic-foot volume on this timberland was estimated at 2.93 billion cubic feet. Timber growth and mortality were estimated at...

Log weights were estimated from the product of Huber's cubic volume formula and green density. Tags showing estimated log weights were attached to logs in the field, and the weights were tallied into a single load weight as logs were assembled for aerial yarding. Accuracy of the estimated load weights was evaluated by comparing the predicted with the actual load weights as measured with scales in a helicopter. A total of 110 loads were evaluated. The load weights were accurate (about 10-percent error), and the method was easily applied under difficult logging conditions. The number of...

We present a technique, based on microhistological analysis of fecal pellets, for quantifying the diets of forest rodents. This technique provides for the simultaneous recording of fungal spores and vascular plant material. Fecal samples should be freeze dried, weighed, and rehydrated with distilled water. We recommend a minimum sampling intensity of 50 fields of view for each of three slides per sample. Absolute and relative percentage of frequencies per sample can then be calculated.

Fishery scientists and managers are interested in obtaining information about downstream movements of fish species for biological and economic reasons. Different types of nets and traps have been used for this purpose with only partial success. The floating, self-cleaning downstream migrant trap described here proved successful for sampling several salmoniform and cypriniform species. The trap functions effectively for several streamflow ranges and handles small floating debris without loss of efficiency. Data from these floating traps show a range of trapping efficiency from 5.0 to 46.6...

Wildlife-habitat models are increasing in abundance, diversity, and use, but symptoms of failure are evident in their application, including misuse, disuse, failure to test, and litigation. Reasons for failure often relate to the different purposes managers and researchers have for using the models to predict and to aid understanding. This paper examines these two purposes and the nature of problems or failures in model application. A five-step approach toward solution is presented: (1) recognize the problem, (2) nurture modeling teams, (3) match purpose with test, (4) confront basic...

The growth response after 20 years from an initial spacing study established in a ponderosa pine (Pinus ponderosa Dougl. ex Laws.) and lodgepole pine (Pinus contorta Dougl. ex Loud.) plantation was measured in central Oregon. The study was designed to compare the growth rates of pure ponderosa pine, pure lodgepole pine, and a 50-percent mixture of each species planted at 6-, 9-, 12-, 15-, and 18-foot spacings. Diameter growth of pure ponderosa pine was greater than that of pure lodgepole pine at all spacings, although pure lodgepole grew faster in height than pure ponderosa. Growth of the...